Disable OVN gateway chassis when evacuated

[stgraber]

As a machine that's evacuated is likely to be going down shortly thereafter, it would make sense for the evacuated state to be tied to either a disabled OVN gateway chassis state or at least a much lower chassis priority.

[Abhiram824]

Could we be assigned to this as well please?

[stgraber]

For this one, you're going to want to look at cmd/incusd/api_cluster.go for the evacuation logic.

The easiest way to have the chassis disabled is going to be by stopping all networks while evacuated. So loading all local networks and calling Stop() on them should do that fine.

You'll also need to add a check to cmd/incusd/daemon.go so that on system startup the networks don't get started when the machine is evacuated (look for networkStartup).

Then you'll need logic in the evacuation restore logic to start the networks back up once the system is fully restored.

[Abhiram824]

Hello! We made some progress and created a draft PR. Does our initial approach look correct?
#747

[dhruvvnistala]

Hi, commenting on this post as per our discussion on #255